Early presence of antiangiogenesis-related adverse events as a potential biomarker of antitumor efficacy in patients with metastatic gastric cancer treated with apatinib.

Abstract

4052 Background: Reliable biomarkers of apatinib response in gastric cancer (GC) are lacking. We investigated the association between early presence of common adverse events (AEs) and clinical outcomes in metastatic GC patients. Methods: We conducted a retrospective cohort study using data on 269 apatinib-treated GC patients in two clinical trials. AEs were assessed at baseline until 28 days after the last dose of apatinib. Clinical outcomes were compared between patients with and without hypertension (HTN), proteinuria or hand and foot syndrome (HFS) in the first 4 weeks using Kaplan–Meier methods, Cox proportional hazard regression and logistic regression models. Landmark analyses were performed as sensitivity analyses. Predictive model and risk scores were analyzed to predict overall survival (OS). Results: Presence of AEs in the first 4 weeks was associated with prolonged median OS (169 vs. 103 days, log-rank p=0.0039; adjusted hazard ratio [HR] 0.64, 95% confidence interval [CI] 0.64-0.84, p=0.001), prolonged median progression-free survival (PFS, 87 vs. 62 days, log-rank p=0.0309; adjusted HR 0.69, 95%CI 0.53-0.91, p=0.007), and increased disease control rate (54.67% vs. 32.77%; adjusted odds ratio 2.67, p<0.001). Results remained significant in landmark analyses. An AE-based prediction model and subsequently derived scoring system showed high calibration and discrimination in predicting OS. Conclusions: Presence of HTN, proteinuria or HFS during the first cycle of apatinib treatment was a viable biomarker of antitumor efficacy in metastatic GC patients. [Table: see text]